Formaldehyde solutions are colourless, sometimes milky, with a pungent odour. It is a COMBUSTIBLE LIQUID AND GAS. Formaldehyde gas released from the solutions can form explosive mixtures with air at, or above 50-85 deg C, depending on the amount of formaldehyde in the solution, as well as the other components of the formaldehyde solution. During a fire, flammable hydrogen gas and irritating and/or toxic gases may be generated. Formaldehyde is VERY TOXIC and may be fatal if inhaled, absorbed through the skin or swallowed. Formaldehyde gas is severely irritating to the eyes and upper respiratory tract. It may damage the lining of the nasal cavity and the upper respiratory tract. Formaldehyde causes lung injury – the effects of which may be delayed. It is CORROSIVE to the eyes and skin and can cause permanent eye injury and severe burns. Formaldehyde is a SKIN SENSITIZER and may cause a severe allergic skin reaction. Formaldehyde is a CANCER HAZARD -- it can cause cancer, and it is a POSSIBLE MUTAGEN -- it may cause genetic damage, based on animal information.

NOTE: Formaldehyde solutions contain other hazardous ingredients, e.g. methanol.

The largest use of formaldehyde is in the manufacture of urea-formaldehyde, phenolic, melamine and polyacetal resins. It is also used as a chemical intermediate for the manufacture of 1,4-butanediol, polyols (e.g. pentaerythritol and trimethylolpropane), hexamethylenetetramine, methylene diisocyanate (MDI), chelating agents (e.g. ethylenediaminetetracetic acid (EDTA) and nitrilotriacetic acid (NTA)), paraformaldehyde and methylene dianiline.

Formaldehyde is also used as a building block for products used to manufacture textile finishing agents; fire-retardant fabrics; crop protection agents; dyes; surface-active agents; processing aids; tanning agents; dispersion and plastics precursors; extraction agents; animal feeds; slow-release fertilizers; perfumes; vitamins; flavourings; and drugs. It is used in agriculture for seed treatment, soil disinfection, and as an insecticide and fumigant; as a reagent in analysis; to water- and grease-proof concrete and plaster; as a hydrogen sulfide scavenger; and biocide in oil production and in the rubber industry for latex; in the metal industry as a corrosion inhibitor, in mirror finishing and electroplating; as a preservative in consumer products (e.g. foods, cosmetics, household cleaning agents), as well as grains, seed dressings, wood, hides and skins; in room fumigants; in embalming fluids; in histopathology to preserve tissue specimens; as a bacteriostatic agent in some foods (e.g. cheese); in the photographic industry as a film hardener; for the electrodisposition of printed circuits; in paper treatment; as a starch modifier; and in the sugar industry to prevent bacterial growth during syrup recovery.

Industrial release of formaldehyde gas can occur at any stage during the production, use, storage, transport or disposal of products containing formaldehyde.

NOTE: The information provided here is for formaldehyde solutions. This information does not necessarily apply to the release of formaldehyde gas to indoor and outdoor environments from natural and/or man-made processes.

Formaldehyde is normally produced and sold as water solutions with concentrations ranging from 25-56 wt% formaldehyde gas. The predominant grade sold is 37% by weight, known as formalin. Methanol is generally added as a stabilizer to prevent polymerization of the formaldehyde. Formaldehyde solutions are sold as low methanol (uninhibited) and high methanol (inhibited) grades. Depending on the grade, formaldehyde solutions may contain 0.5-15% methanol. Other stabilizers used include other alcohols (e.g. ethanol, propanol or butanol), guanamines (e.g. isophthalobisguanamine), alkalenebis(melamines), melamine, hydroxypropylmethylcellulose, methyl- and ethylcelluloses or poly(vinyl alcohol)s at concentrations ranging from 10-1000 ppm. The presence of stabilizers, like methanol, in formaldehyde solutions can significantly influence the overall hazards of the product.

Formaldehyde solutions are also known as formalin, formic aldehyde, methaldehyde, methanal, methyl aldehyde, methylene oxide, oxomethane, and oxymethylene.

Its CAS Registry Number is 50-00-0. This number is assigned by the Chemical Abstracts Service (CAS) in the United States and is used as a unique identifier number world-wide.